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Sergey Doroshenko commented on ZOOKEEPER-704: --------------------------------------------- Dave, thanks for feedback, Did you check http://wiki.apache.org/hadoop/ZooKeeper/GSoCReadOnlyMode ? Approach described there is similar to what you've proposed: make server distinguish read-only and usual clients. However, I was thinking that r-o client should go to read-only mode right after server it's tied to is partitioned, without trying to reconnect to majority. But your idea that client should try all servers first is definitely a better option. Also I think current behavior of ZooKeeper client should remain unchanged. I mean, there should be either new class for r-o client, or new functionality in current client which is explicitly triggered say by a flag passed to ctor. The idea is not to break code for current users. > GSoC 2010: Read-Only Mode > ------------------------- > > Key: ZOOKEEPER-704 > URL: https://issues.apache.org/jira/browse/ZOOKEEPER-704 > Project: Zookeeper > Issue Type: Wish > Reporter: Henry Robinson > > Read-only mode > Possible Mentor > Henry Robinson (henry at apache dot org) > Requirements > Java and TCP/IP networking > Description > When a ZooKeeper server loses contact with over half of the other servers in > an ensemble ('loses a quorum'), it stops responding to client requests > because it cannot guarantee that writes will get processed correctly. For > some applications, it would be beneficial if a server still responded to read > requests when the quorum is lost, but caused an error condition when a write > request was attempted. > This project would implement a 'read-only' mode for ZooKeeper servers (maybe > only for Observers) that allowed read requests to be served as long as the > client can contact a server. > This is a great project for getting really hands-on with the internals of > ZooKeeper - you must be comfortable with Java and networking otherwise you'll > have a hard time coming up to speed. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.